The number of CT exams performed on patients has dramatically increased during the past few years, which has resulted in a higher risk of developing cancer for the patients due to the radiation dose received during the CT scans. Radiation dose to patients continues to be a significant concern to medical physicists and to the broader medical community as well. Radiation dose from CT exams has been identified as the largest source of medical radiation exposure. The knowledge of radiation dose to individual organs in the body is currently considered as the optimal means to estimate patient dose from CT.
Various approaches have been developed to reduce radiation dose from CT scans to patients, including tube current modulation (TCM), adjusting/lowering mAs for patient size, and lowering kVp (especially for studies using iodinated contrast), all while maintaining the diagnostic image quality that is so important in CT. These techniques have been very effective at reducing overall radiation dose to the patient. However, they have not been very anatomically specific, nor have they targeted specific radiation sensitive organs for radiation dose reduction. These approaches have been based on the overall size and shape (and other characteristics, such as the attenuation of the X-ray beam by the body) of the patient, and therefore have sought to reduce the overall radiation dose to the patient.